Bandage application for applying medications to compromised skin, whether merely slightly broken (scrapes or small cuts) or severely compromised such as in severe large scale burns require bandages to be very gingerly applied and removed so as to avoid disturbing the healing process. Transdermal and topical bandages usually have adhesives associated therewith that adhere to skin very well and make it difficult to remove and change bandages without significant pulling on skin or causing substantial stresses and torques on the injured area. These situations result in re-injury to the healing site or further opening and sometimes expanding would area, even when the adhesive is on the periphery of the wound site. Further, where the skin or wound area being dressed has scabs, friability, or hairs, the removal of adhesives from the skin can be painful. In addition, in older patients, or those with arthritic conditions, the removal of adhesive dressings can be quite difficult.
In many transdermal contexts, whether with or without the foregoing issue, a significant difficulty involves skin irritation, frequently due to the skin-contacting adhesives being utilized to secure the transdermal to the body. Because of such irritation, transdermal patches have traditionally been made as small as possible so that as small a region as possible is affected (and leaving alternate application sites for rotation of application of subsequent dosages while the prior application site recovers). The size limitation of the transdermal patch means that for many drugs, the formulations must have a flux enhancer in order to achieve a sufficient delivery rate (inherent delivery rate/unit area X area of application) for an efficacious product. Unfortunately, flux enhancers frequently are themselves irritating to the skin and thus, more times than not, just exacerbate the problem. Still other drugs, even with the flux enhancers, have insufficient delivery rates from trandermals of the conventional sizes.
In further contexts, certain drugs have been incompatible with various adhesives (chemical or physical instability of the drug) or plasticize (or “soften”) the adhesive through which it must pass or in which it is embedded), meaning that the number and kind of adhesives that can be used are limited, often leaving only the more irritating adhesives as the only suitable ones, or resulting in devices in which the drug containing layer partially pulls away from the device when its “release liner” is removed or the device tends to fall off the patient prematurely, either way resulting in underdosing of the patient.
Some attempts have been made to increase drug flux through the skin, with and without permeation enhancers by using various energy sources to help drive the material through the skin. These include iontophoretic systems (utilizing charged moieties and applied current), sonophoretic systems (utilizing ultrasonication), photophoretic systems (utilizing (generally non-ablative) laser energy), etc. Other attempts have been made using liposomal encapsulation to take advantage of liposomal transport and fairly recently nanoenapsulation (delivery of proteins such as insulin and other large molecules across skin).
The present invention addresses these issues in the transdermal context by removing the need for the skin-contacting adhesive, allowing the size of the transdermal to be increased, which then permits efficacious delivery of materials with lower inherent flux rates as the total delivery per unit time is increased ((inherent flux)×(area of device)). This allows for reduction or elimination of the flux enhancers, so as to further avoid skin irritation, and allows for the application of transdermal technology to a range of molecules to which it could not be applied previously. The coupling of the present dressing devices with or the incorporation within the present dressing devices of various driving energy structures (iontophoretic, sonophoretic, pulsed electronic, and/or photophoretic) further expands the range of molecules that can be delivered, as does the use of liposomal and nano-encapsulations.